25 Jan
2006
25 Jan
'06
5:34 p.m.
I've got two PCs which I use mainly for watching video with MPlayer (for
various reasons Xine isn't so practical) and it has A/V sync problems on
them. I think it may be because my cheap & nasty sound cards lack some
feature that MPlayer relies on to sync properly:
<http://www.mplayerhq.hu/DOCS/HTML/en/audio.html#sync>. Unfortunately it
doesn't say exactly what the feature is and which are the bad drivers.
One of the PCs has a cheap sound card using the snd_cmipci driver and
the other has VIA onboard audio. The former also sometimes makes speech
sound a bit muffled I think.
I've heard of an "AC3 passthrough" feature. Does that mean the sound
card decodes the audio stream instead of the CPU? Although I don't have
a surround system ATM, I think it would be a nice feature to have in
case I install one later. Meanwhile, would AC3 passthrough work for
stereo AC3 streams?
So what would be a good card to get? I've heard that the Turtle Beach
Santa Cruz is supposed to be very good, and I know it is supported by
Linux, but I haven't been able to find out how well or whether it's
likely to fix the A/V sync. I should be able to get one (or two) on eBay
at a reasonable price.
--
TH * http://www.realh.co.uk
26 Jan
26 Jan
5:53 a.m.
On Wed, Jan 25, 2006 at 09:34:24PM +0000, Tony Houghton wrote:
I've got two PCs which I use mainly for watching
video with MPlayer (for
various reasons Xine isn't so practical) and it has A/V sync problems on
them. I think it may be because my cheap & nasty sound cards lack some
feature that MPlayer relies on to sync properly:
Strange, I've been using both the CMI8738 (an excellent chipset for some
applications) and Via Ac97 for years without any sync problems in Mplayer.
What problems are you having? Sync slowly drifting out?
cheers
--
Tim
2:28 p.m.
In <20060126094721.GA25389@sofa>, Tim Orford wrote:
On Wed, Jan 25, 2006 at 09:34:24PM +0000, Tony
Houghton wrote:
It's probably not so much the chipset as the cheap card it's on, which
could compromise the accuracy of its clock and have poor quality
analogue components. So I think getting a better card may improve things
anyway. Worth a try.
I've got two PCs which I use mainly for
watching video with MPlayer (for
various reasons Xine isn't so practical) and it has A/V sync problems on
them. I think it may be because my cheap & nasty sound cards lack some
feature that MPlayer relies on to sync properly:
Strange, I've been using both the CMI8738 (an excellent chipset for some
applications) and Via Ac97 for years without any sync problems in Mplayer. What problems are you having? Sync slowly drifting
out?
I'm outputting to a TV from a Matrox G450 with DirectFB so MPlayer can't
simply adjust the framerate. It used to drift until I tweaked MPlayer's
options. I think these fixed that problem:
framedrop=1
autosync=30
But I was left with a fixed A-V delay that would tend to differ from
file to file, but if I adjusted MPlayer's A-V delay it would usually
stay OK all the way through that file. But sometimes each time I tried
to adjust the delay, the discrepancy would change with it, so I could
never get it right.
Someone on another list pointed out to me that MPlayer's alsa driver is
buggy so I switched to -ao oss and that seems to have just about cured
it. NB -ao sdl has the same problem as alsa, at least if SDL is using
alsa.
I also have the fixed A-V delay problem with vdr-softdevice though,
which lacks any of MPlayer's flexibility to fix or work around it.
--
TH * http://www.realh.co.uk
1:23 p.m.
On Wed, Jan 25, 2006 at 09:34:24PM +0000, Tony Houghton wrote:
I've heard of an "AC3 passthrough"
feature. Does that mean the sound
card decodes the audio stream instead of the CPU? Although I don't have
a surround system ATM, I think it would be a nice feature to have in
case I install one later. Meanwhile, would AC3 passthrough work for
stereo AC3 streams?
That means it passes the AC3 out the SPDIF port of the sound card so
that an external AC3 decoder (say a Dolby DP564) can decode the audio.
So what would be a good card to get? I've heard
that the Turtle Beach
Santa Cruz is supposed to be very good, and I know it is supported by
Linux, but I haven't been able to find out how well or whether it's
likely to fix the A/V sync. I should be able to get one (or two) on eBay
at a reasonable price.
You haven't given a price range. Personally, the MAudio 2496s seem
pretty nice. But, I don't know that any card is going to automatically
fix your problems.
As someone else asked, you need to describe the sync problems in more
detail. Is it a fixed offset? Is it steadily drifting in one direction
(i.e. the audio is sync at the beginning, but after 1 minute is 1/2
second off, 2 minutes it is a second off, etc). Is it wobbling
(sometimes in sync, sometimes not, moving back and forth?
Just to run through what I've used recently, I've used the SiS sound on
a Shuttle (crappy sound quality, but it doesn't have sync problems), the
sound in a Centrino chipset (not too bad, and still no sync problems), a
MAudio 2496 (I like them, but maybe overkill for you, and still no sync
problems), a SB Live 5.1 Gamer card, and a SB Audigy card (both also
without sync problems). All with mplayer (I prefer mplayer and find it
to more flexible than xine, although in someway not as nice for playing
DVDs as xine is).
--
Joshua D. Boyd
jdboyd(a)jdboyd.net
http://www.jdboyd.net/
http://www.joshuaboyd.org/
6905
days inactive
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3 comments
3 participants
participants (3)
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Joshua Boyd -
Tim Orford -
Tony Houghton